According to users and analysts, the impending exits of both of IBM s plug-compatible mainframe rivals from the S/390 market focuses more attention on the real high-end server battle: the one between IBM's big-iron boxes and Unix systems made by vendors such as Sun Microsystems and Hewlett-Packard.
Two weeks ago, Amdahl Corp. said it plans to quit the mainframe business because the cost of staying competitive with the 64-bit zSeries 900 systems that IBM announced last month was too high when compared to the projected returns on that investment. The move by Sunnyvale, Calif.-based Amdahl came just seven months after Hitachi Data Systems Corp. in Santa Clara, Calif., announced that it would stop selling mainframes to new customers and would focus on Unix systems going forward -- a strategy similar to what Amdahl has in mind.
Analysts said the planned departures of Amdahl and Hitachi from the mainframe business should allow IBM to avoid hardware price reductions, especially for higher-end S/390 systems that Unix servers still can't match on performance and scalability. But growing competition from a new generation of powerful Unix servers could temper IBM's moves in the lower end of the mainframe market, industry watchers noted.
"I think that for the last couple of years, IBM's competition ... was not coming from plug-compatible vendors but primarily from Sun and [other Unix vendors]," said Dan Kaberon, Parallel Sysplex manager at Hewitt Associates LLC in Lincolnshire, Ill.
That's because technologies such as partitioning, sophisticated I/O and workload management capabilities, as well as support for more processors and larger memory capacities, are pushing high-end Unix servers ever closer to mainframelike performance, said Jonathan Eunice, an analyst at Illuminata Inc. in Nashua, N.H.
"In terms of raw memory or storage or processor [support], Unix servers are, in fact, better than mainframes," Eunice said. "The strong point for the mainframe is in handling integrated workloads where you need not only a lot of computing power but also transaction handling and I/O at very sustained rates."
"Unix is in a very good position to expand from its midrange franchise," agreed Jean Bozman, an analyst at International Data Corp. in Framingham, Mass. "Any workload can run on either a Unix server or a mainframe. The difference really is the higher level of reliability and security available on mainframes."
Areas where mainframes still clearly hold the edge over Unix servers include their ability to handle multiple workloads, the way S/390 hardware and software are tuned to take maximum advantage of each other, the availability of superior middleware and the overall maturity of big-iron technology in enterprise applications, Eunice said.
The growing sophistication of Unix servers comes at a time when mainframe server growth seems to be flattening out. Stamford, Conn.-based Meta Group Inc. estimates that the net growth of installed mainframe capacity will be about 19% this year, compared with 33% a year ago. And while Unix server prices have been creeping ever closer to what users are charged for mainframe hardware, it still costs a lot more to run software on S/390 systems.
Because of that, the performance level at which it becomes more cost-effective to run applications on a mainframe instead of a Unix server has risen from about 500 MIPS two years ago to nearly 1,000 MIPS today, said Carl Greiner, a Meta analyst. "You have to be a pretty big shop to buy a mainframe," he add. "You're not going to find many new organizations and dot-coms looking at mainframes as an alternative.